Endocrinology, Vol 127, 2947-2954, Copyright © 1990 by Endocrine Society

ARTICLES

Luteinizing hormone causes rapid and transient changes in rat Leydig cell peroxisome volume and intraperoxisomal sterol carrier protein-2 content

SM Mendis-Handagama, PA Watkins, SJ Gelber, TJ Scallen, BR Zirkin and LL Ewing
Department of Population Dynamics, Johns Hopkins School of Hygiene and Public Health, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.

The aim of the present study was to investigate the effects of a single injection of LH on rat Leydig cell peroxisome volume and peroxisomal sterol carrier protein-2 (SCP2) content. Sexually mature Sprague-Dawley rats (n = 5) were injected sc with 500 micrograms LH and euthanized, and trunk blood was collected at 0, 0.5, 1, 2, and 3 h. Additionally, LH-treated rats were whole body perfused-fixed, and their testes were processed for qualitative and quantitative histochemical and immunocytochemical studies at 0, 0.5, 1, and 2 h. Peroxisomes were identified by cytochemical staining for catalase activity with the alkaline 3,3'-diaminobenzidine tetrahydrochloride method. Catalase and SCP2 were immunolocalized in Leydig cell organelles via 10-nm AuroProbe EM protein-A gold particles. Peak plasma testosterone concentrations were observed 1 and 2 h after the single sc LH injection. The average volume of a Leydig cell was unchanged by the LH treatment at all time points tested. Similarly, the absolute volumes of smooth endoplasmic reticulum and mitochondria per Leydig cell were unchanged at all time points tested. By contrast, the absolute volume of peroxisomes per Leydig cell increased 3-fold 0.5 h after LH injection (P less than 0.01) and then returned to control values by 2 h. The absolute volume of negative bodies (single membrane-bound cytoplasmic organelles lacking catalase) per Leydig cell was elevated above the control value 0.5 and 1 h after LH injection. Western blot analysis demonstrated a single protein at 14 and 60 kDa with anti-SCP2 and anticatalase, respectively, for both homogenates obtained from liver and purified Leydig cells. Quantitative immunocytochemical studies demonstrated that the gold particle density representing SCP2 over peroxisomes increased 5-fold 0.5 h after the LH injection (P less than 0.01) and then returned to control values by 2 h. In contrast, the gold particle density representing catalase over peroxisomes was not different in control and LH-injected groups. We conclude that a single sc injection of LH causes a rapid, specific, and transient increase in both the volume of peroxisomes and the peroxisomal content of SCP2 in Leydig cells.

This article has been cited by other articles:

				P. Murugesan, M. Balaganesh, K. Balasubramanian, and J. Arunakaran Effects of polychlorinated biphenyl (Aroclor 1254) on steroidogenesis and antioxidant system in cultured adult rat Leydig cells J. Endocrinol., February 1, 2007; 192(2): 325 - 338. [Abstract] [Full Text] [PDF]

				F. Schroeder, A. M. Gallegos, B. P. Atshaves, S. M. Storey, A. L. McIntosh, A. D. Petrescu, H. Huang, O. Starodub, H. Chao, H. Yang, et al. Recent Advances in Membrane Microdomains: Rafts, Caveolae, and Intracellular Cholesterol Trafficking Experimental Biology and Medicine, November 1, 2001; 226(10): 873 - 890. [Abstract] [Full Text] [PDF]

				S.M.L.C. Mendis-Handagama, H.B.S. Ariyaratne, K.R. Teunissen van Manen, and R.L. Haupt Differentiation of Adult Leydig Cells in the Neonatal Rat Testis Is Arrested by Hypothyroidism Biol Reprod, August 1, 1998; 59(2): 351 - 357. [Abstract] [Full Text]

				C. L. Baum, E. J. Reschly, A. K. Gayen, M. E. Groh, and K. Schadick Sterol Carrier Protein-2 Overexpression Enhances Sterol Cycling and Inhibits Cholesterol Ester Synthesis and High Density Lipoprotein Cholesterol Secretion J. Biol. Chem., March 7, 1997; 272(10): 6490 - 6498. [Abstract] [Full Text] [PDF]