17β-Estradiol synthesis in the adult male rat retina

The estrogenic retina: The potential contribution to healthy aging and age-related neurodegenerative diseases of the retina

“…2). All these enzymes are present in the retina at lower amounts when compared to those of peripheral glands (testes and adrenals) [5], but similar to those exhibited by other CNS structures [38].…”

“…In 2001, Salyer et al [37], suggested that retinal thickness was affected following testosterone conversion into E2 in the RPE, having a possible implication in sexual dimorphism of visual processing in rodents and humans. Subsequent studies from our and other laboratories reported expression and activities of the key neurosteroidogenic enzymes that now allow to define the landscape of E2 synthesis starting from cholesterol or from testosterone throughout the retina [2,3,5] (see Fig. 2 for a schematic representation of the distribution of neurosteroid enzymes and E2 neurosteroidogenic pathway in the retina).…”

“…Subsequently, it was discovered that the oestrogen 17β-oestradiol (E2) is locally formed in the retina via a cholesterol-based synthesis and testosterone aromatization [2,5]. As well, oestrogen, androgen, progesterone, mineralcorticoid and glucocorticoid receptors were identified throughout the eye regions, including the retina [5,[6][7][8][9][10][11][12]. These findings opened up new avenues of the eye research, revealing previously unknown signaling substrates, the neurosteroids, and the likelihood that locally synthesized neurosteroid E2 could influence visual processing and eye diseases.…”

Pregnenolone Biosynthesis in the Rat Salivary Gland and Its Inhibitory Effect on Secretion

“…However, PRG may act on not only GABA A -R in the salivary gland, as BIC did not completely block the inhibitory effects of PRG. Some studies have suggested that organs such as the brain (7 -10), gonad gland (27), retina (28), lung (29), kidney (30), and pancreas (31) are capable of self-supplying a small amount of steroids. These steroids are believed to be intermediate products on the way to the final metabolite in the steroidal production process and to be involved in physiological control of cellular function.…”

Progesterone Treatment in Two Rat Models of Ocular Ischemia

“…[59][60][61][62][63] Further support for progesterone's ability to act in the eye is demonstrated by studies showing that changes in endogenous progesterone levels affect a variety of ocular functions in humans from intraocular pressure 64,65 to visual function. 66,67 This idea is supported by previous research demonstrating protective effects of progesterone or progestins in models of light-induced retinal degeneration 68 and pressure-induced retinal ischemia-reperfusion.…”