Glutamine Amino Acid in Proliferation
Sebum is produced when the sebaceous gland disintegrates. The cells take about a week from formation to discharge.

Glutamine is a nutrient for immune cells and acts as precursor for glutathione, which circumvents oxidant stress and improves cell-mediated immunity.1

Cholesterol 3-Sulfate Interferes with Cornified Envelope Assembly by Diverting Transglutaminase 1 Activity from the Formation of Cross-links and Esters to the Hydrolysis of Glutamine 2

The skin contains all the enzymes needed for transformation of cholesterol to steroids. Moreover, the sebaceous glands express 5a-reductase (especially in face/scalp), needed for the intracellular conversion of testosterone to the more potent 5a-dihydrotestosterone. Moreover, these glands are part of the skin neuroendocrine system as they produce and release corticotrophin-releasing hormone (in response to stress). The human sebaceous gland is both glycolytic and glutaminolytic; the sugar glucose is converted to lactate, and glutamine is converted to glutamate, alanine, serine, glycine, threonine, lactate and ammonia. Recently, it has been shown that exogenous glutamine is required for sebocyte division and lipogenesis, though it can be replaced by spermidine.

Lipogenesis in Human Sebaceous Gland: Glycogen & Glycerophosphate are Substrates for the Synthesis of Sebum Lipids

Although preliminary experiments have shown that human sebaceous glands engage in glutaminolysis, and also that, in the absence of glutamine, rates of lipogenesis and DNA synthesis are reduced, glutamine demonstrated poor lipogenic capacity. This may suggest that, although glutamine may be important for sebaceous cell proliferation, in contrast to the hair follicle (Williams et al. 1993) the sebaceous gland does not utilize glutamine as an important catabolic fuel.

Keratinocytes as Depository of Ammonium-Inducible Glutamine Synthetase: Age- and Anatomy-Dependent Distribution in Human and Rat Skin

In inner organs, glutamine contributes to proliferation, detoxification and establishment of a mechanical barrier, i.e., functions essential for skin, as well. However, the age-dependent and regional peculiarities of distribution of glutamine synthetase (GS), an enzyme responsible for generation of glutamine, and factors regulating its enzymatic activity in mammalian skin remain undisclosed. .... Such a depository of glutamine-generating enzyme seems essential for continuous renewal of epidermal permeability barrier and during pathological processes accompanied by hyperammonemia.

Human sebaceous glands engage in aerobic glycolysis and glutaminolysis (NIH)

Background The skin and its appendages support aerobic glycolytic and glutaminolytic metabolism. Their major fuels are glucose and glutamine, which are, however, largely catabolized anaerobically.

Objectives For the human sebaceous gland it has been reported that glucose, lactate and acetate provide good lipogenic substrates but that glutamine does not. Therefore, we have investigated the intermediary metabolism in vitro of freshly isolated human sebaceous glands to determine if their metabolism of glutamine is anomalous relative to the rest of the skin.

Methods Glycolytic rate, glucose and glutamine oxidation, and glucose metabolism by the pentose phosphate pathway were determined in freshly isolated human chest sebaceous glands. Further, sebaceous intermediary metabolites were analysed using spectrophotometry and high-performance liquid chromatography. Moreover, glands were maintained in vitro as whole organs to investigate the effects of precursors and inhibitors of polyamine synthesis on rates and patterns of lipogenesis and DNA synthesis.

Results We confirm that the human sebaceous gland is a glycolytic and glutaminolytic tissue. Glucose is mainly converted to lactate, with only 6% of glucose being oxidized to CO2. Glutamine is largely converted to glutamate, alanine, serine, glycine, aspartate, threonine, lactate and ammonia, with only 12% being oxidized. We have also shown that exogenous glutamine is required for cellular proliferation and lipogenesis by human sebaceous glands. However, in its absence spermidine could fully restore rates of DNA synthesis and lipogenesis.

The induction of lipase activity in the germinating wheat grain ...by RJA Tavener - 1972 - lipase activity can be induced in the starchy endosperm by one of several nitrogenous compounds, in particular glutamine.

How much glutamine is needed?

The typical American diet provides 3.5 to 7 grams of glutamine daily which is found in animal and plant proteins. Many people are choosing to supplement daily due to the long growing list of benefits.

Research shows levels of supplementation from 2 to 40 grams daily. Two to three grams has been found to help symptoms of queasiness. This two to three gram dosage used post workout builds protein, repairs and builds muscle and can induce levels of growth hormone found in the body.

Mutagenesis and heterologous expression in yeast of a plant D6-fatty acid desaturase - Oxford Journals

Membrane-bound microsomal fatty acid desaturases are known to have three conserved histidine boxes, comprising a total of up to eight histidine residues. Recently, a number of deviations from this consensus have been reported, with the substitution of a glutamine for the first histidine residue of the third histidine box being present in the so called ‘front end’ desaturases. These enzymes are also characterized by the presence of a cytochrome b5 domain at the protein N-terminus. Site-directed mutagenesis has been used to probe the functional importance of a number of amino acid residues which comprise the third histidine box of a ‘front end’ desaturase, the borage D6-fatty acid desaturase. This showed that the variant glutamine in the third histidine box is essential for enzyme activity and that histidine is not able to substitute for this residue. In this study it is demonstrated that replacement of the glutamine residue by histidine or isoleucine in the third histidine box of the cytochrome b5-fusion ‘front end’ D6-fatty acid desaturase abolishes enzyme activity. It is also shown that mutations within and around the third histidine box reduce the activity, but do not alter the specificity of this enzyme. The experimental data therefore indicate that the consensus motif for the third histidine box of ‘front end’ desaturases should be amended to Q-X[2-3]-H-H, since substitution of this glutamine residue by histidine is not tolerated.

Inflammation rather than nutritional depletion determines glutamine concentrations and intestinal permeability.

Mutagenesis of the borage Delta-6 fatty acid desaturase in presence of glutamine.