The inhibition by testis microsomes of corticosterone formation by adrenal mitochondria

Seasonal Changes in the Newt, Trituroides hongkongensis, Testis. II. An Ultrastructural Study on the Lobule Boundary Cell

“…The abundance of smooth endoplasmic reticulum in the LBC at certain stages is a common feature found in steroid-producing tissues, and biochemical evidences suggest that it is the site for enzymes mediating steroids biosynthetic pathways (Lynn and Brown 1958, Hoffmann 1962, Christensen 1965, Shikita et al 1964, Shikita and Tamaoki 1965. Moreover, the location of 5-ene-3P-hydroxysteroid dehydrogenase has been reported in the smooth endoplasmic reticulum by various authors (Beyer andSamuels 1956, Bjersing 1967).…”

The Fine Structure of Testicular Interstitial Cells in Guinea Pigs

“…dominantly in the microsome fraction of guinea pig testis homogenates (32,22) and are stable to ribonuclease (32), suggesting that these enzymes are associated with the membranes of the microsome fraction and not with the ribosomes. It is assumed, for the purposes of the present study, that this reflects the location of these enzymes in living ceils, although there is always the danger in cell fractionation studies that during homogenization some enzymes may be adsorbed secondarily onto structures that they did not occupy when the cell was intact.…”

“…In addition to their probable role as an energy source, the mitochondria of rat interstitial cells are the site of the enzymes that cleave the side chain of cholesterol to make pregnenolone (52). Since the enzymes that precede this stage of androgen A. KENT CItRISTENSEN Guinea Pig Interstitlal Cells Microsomes: rat (50) Microsomes: guinea pig (32,22), rat (50,51,32) Microsomes: guinea pig (32,22), rat (50,51,32) Microsomes: guinea pig rat (50, 51) Soluble: guinea pig (32) (22), biosynthesis and those that follow it are predominantly in the microsome fraction, presumably cholesterol must pass from the vicinity of the endoplasmic reticulum to the mitochondria, and pregnenolone must return to the reticulum. If the cholesterol cleavage enzymes are inside the mitochondria, rather than on their surface, then there might be some accumulation of substrates within the mitochondria, which could explain the dense matrix that is a common feature of interstitial cell mitochondria as seen in electron micrographs.…”

“…The pigment appears dense and homogeneous in OsO4-fixed material (Figs. 17,20,and 22), but is less dense after prefixation in glutaraldehyde (Figs. 3 and 18).…”

“…The present study overcomes this difficulty by elucidating the fine structure of interstitial cells in guinea pigs, a species used for some of the pertinent biochemical work (32,22).…”