The fine structure of regenerating adrenocortical autotransplants in the rat

Abstract

The fine structural changes accompanying the regeneration of adrenocortical transplants in the rat were studied with the electron microscope. One-half gland autotransplants were made to the dorsal musculature of male Wistar rats, weighing approximately 120 gm. Transplants were recovered after 2, 4, 7, 14, 21 and 60 days of regeneration. During the first week of regeneration there was a n increase in the granular endoplasmic reticulum at the expense of the agranular form. The internal structure of the numerous mitochondria was tranformed from the normal tubular and vesicular forms of the zonae glomerulosa and fasciculata, respectively, to a lamellar type. The quantities of free ribonucleoprotein particles also were reduced. During this period the viable cortical cells are considered to be more deeply involved in protein synthesis and growth rather than hormone biosynthesis. Following 14 days of regeneration and thereafter, the characteristics of the normal intact adrenal cortex became established. Highly osmiophilic "dark cells," present in the inner zones of the normal intact adrenal cortex, first appeared after 14 days of regeneration, and were widely scattered throughout the cortex after three weeks. After two months of regeneration, the "dark cells" were again concentrated in the inner cortical zones. During this latter period, hormone biosynthesis appears to be the major cell function. Possible structural-functional relationships are discussed.

Modulation of autotransplanted adrenal gland by endothelin‐1: A morphological and biochemical study

“…Therefore, our results might reflect the effect of a direct stimulation (ET-1 receptors) of a "hybrid" cell pool located between the two outer and inner zonae, irreversibly directed to fasciculata differentiation. These cells seem like reticularis cells; however, they disclose neither the "aging pigment" lipofuscin nor apoptotic figures usual in reticularis cells (Penney et al, 1963;Rhodin, 1971;Wyllie et al, 1980). In the same way, the increased number of glomerulosalike cells (with or without stimulation features) reflect the stimulation of these cells, which can present ET-1 receptors.…”

Autotransplantation of the adrenal cortex: A morphological and autoradiographic study

“…DISCUSSION When adrenal gland autotransplantations were first performed some years ago, the basic purpose was to define the gland regeneration process (Ingle and Higgins, 1938;Greep and Deane, 1949;Brenner et al, 1953;Penney et al, 1963;Seki et al, 1969;Taki and Nickerson, 1985). Autotransplantation success was achieved above all in rodents, which is why rats and mice are the animals of choice in most experiments (Wyman and Suden, 1932;Baxter, 1946;Greep and Deane, 1949;Brenner et al, 1953;Penney et al, 1963;Murakami and Takahashi, 1982;Saxe and Connors, Figs. 12-1 5. LM autoradiographs of adrenal grafts after c3H1 thy- Postautotransplantation-2 days.…”

Rat Adrenal Transplants are Reinnervated: An Invalid Model of Denervated Adrenal Cortical Tissue

“…Immunolabelling for P45011β and P450aldo in transplanted adrenals was used to define the recovery and location of fasciculata and glomerulosa cells, respectively. Previous studies examining recovery of zonation after transplantation have been inconsistent; both the presence ( 40, 41) and the absence ( 42, 43) of zonation has been reported in regenerating adrenal transplants. In studies employing an antibody that binds selectively to inner adrenal zones ( 44), recovery of the zona fasciculata was clearly defined.…”