Localization and Hormonal Regulation of the Non-Specific Lipid Transfer Protein (Sterol Carrier Protein2) in the Rat Testis

Abstract

In testis tissue from mature rats the non-specific lipid transfer protein (nsLTP), also called sterol carrier protein2 (SCP2), is concentrated in the Leydig cells and cannot be detected in Sertoli cells or germinal cells. Conclusions were reached after cell fractionation studies with normal testis tissue and after selective destruction of Leydig cells or germinal cells in vivo. The amount of nsLTP (SCP2) in testis tissue increased twofold 48 h after two daily injections of human chorionic gonadotrophin (100 i.u., s.c.) and decreased twofold after plasma luteinizing hormone levels were suppressed to almost undetectable levels with silicone elastomer implants containing testosterone. The specific localization in the Leydig cells and the luteinizing hormone-dependent cellular concentration of nsLTP/SCP2 support the possibility that this protein could play a role in the regulation of steroidogenesis by regulating the availability of cholesterol for the P450 side-chain cleavage enzyme in the mitochondria of Leydig cells.

Putative rat sperm lipid‐binding protein: Isolation and partial characterization

“…Lipid-binding and transfer proteins are ubiquitous cytosolic proteins involved in lipid metabolism and the exchange of phospholipids such as phosphatidylcholine (PC), phosphatidylinositol (PI), phosphatidylethanolamine (PEA and sphingomyelin between membranes. An example is the sterol carrier binding protein-(SCP2) that stimulates the transfer of cholesterol from the outer to inner membrane of mitochondria in rat Leydig cells and thus may regulate steroidogenesis (van Noort et al, 1986). Other lipid-transfer proteins have been described that are testis specific, such as a 41-kD phosphatidylinositol-transfer protein found only in adult rat testis, and presumably only in the seminiferous tubule (Thomas et al, 1989).…”

Further analysis of the disturbed adrenocortical function in the cerebro‐hepato‐renal syndrome of zellweger

“…Recently, Van Amerongen and colleagues (1987) reported extremely low levels of non-specific lipid transfer protein (sterol carrier protein 2) in liver tissue of cerebro-hepato-renal syndrome patients. The involvement of non-specific lipid transfer protein in the transfer of cholesterol to mitochondria in steroidogenic cells (Van Noort et al, 1986), and its possible absence from these cells in cerebrohepato-renal syndrome patients may contribute to the impaired synthesis of cortisol after ACTH administration (Van Amerongen et aI., 1987). Our results in patients with cerebro-hepato-renal-syndrome point to a defect prior to progesterone, which may be due to an abnormality of the ACTH receptor on the adrenal fasciculata cell.…”

Coordinated transcriptional regulation patterns associated with infertility phenotypes in men

“…Interestingly, the genes scoring lowest on this axis (correlated negatively with inflammatory gene expression) include known Leydig cell genes such as Insl3 17 and sterol carrier protein 2. 18 Genes scoring highly on the PCA2 axis also scored highly on the PCA1 axis, indicating that increased inflammatory gene expression correlates with absence of germ-cell gene expression and thus with the severity of the testicular phenotype.…”