Biology and sexual orientation INAH3 weight for the heterosexual male brains was significantly larger than for the heterosexual female brains, while the results for the gay male group were between those of the other two groups but not quite significantly different from either. The neuron count also found a male-female difference in INAH3, but found no trend related to sexual orientation. A 2010 study, Garcia-Falgueras and Swaab asserted that "the fetal brain develops during the intrauterine period in the male direction through a direct action of testosterone on the developing nerve cells, or in the female direction through the absence of this hormone surge.
Alpha-Melanocyte-stimulating hormone melanotan II, the former of which being in phase-III clinical trials in the United States. Bremelanotide, another analogue of α-MSH, is currently under development not as a photoprotective agent, but instead for the treatment of sexual dysfunction. All of these drugs have significantly greater potencies than α-MSH, along with improved pharmacokinetics and distinctive selectivity profiles. Alpha-Melanocyte-stimulating hormone α-Melanocyte-stimulating hormone (α-MSH) is an endogenous peptide hormone and neuropeptide of the melanocortin family, with a tridecapeptide structure and the amino acid sequence Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH. It is the most important of the melanocyte-stimulating hormones (MSHs) (also known as melanotropins) in stimulating melanogenesis, a process