Insulin-binding sites in the mouse deferent duct

et al. 2000

Microsc. Res. Tech.

Self Cite

We investigated the distribution of radioactivity from (14)C-labeled gamma-aminobutyric acid (GABA) in the mouse by in vivo autoradiography to clarify the tissues that show GABA uptake and/or GABA binding. Male mice were injected intravenously with (14)C-GABA in both the absence and presence of an excess of unlabeled GABA, baclofen and isoguvacine. Whole-body autoradiography of (3)H-baclofen, a GABA(B) receptor agonist was also performed. At short intervals after (14)C-GABA injection ( 3 and 6 minutes), very high radioactivity was detected in the kidney cortex, liver, pineal gland, hypophysis, median eminence of the hypothalamus, and cervical ganglion. The hyaline cartilage and glandular part of the stomach showed moderate radioactivity. In the presence of an excess amount of unlabeled GABA, radioactivity in most of tissues decreased significantly, but no significant difference in radioactivity was observed in the presence of baclofen and isoguvacine, agonists of GABA(A) and GABA(B) receptors, respectively. Autoradiography of (3)H-baclofen showed that the kidney had high level of radioactivity, whereas the activity in other tissues and organs was similar or lower than in the blood except for the content of the urinary bladder and the pancreas at 15 minutes after injection. These data indicate that radioactivity from incorporated (14)C-GABA into a variety of cells is much higher than that from bound (14)C-GABA to the receptor sites. Our results suggest that GABA can be quickly localized in many organs of the mouse body after 3 minutes following injection, and GABA may serve multiple functions in those organs.

Section: Discussionmentioning

confidence: 99%

Autoradiographic distribution of radioactivity from 14C-GABA in the mouse

Kuroda

et al. 2000

Microsc. Res. Tech.

Self Cite

“…In the reproductive system, the deferent duct showed relatively high insulin binding in the in vivo whole body autoradiograph (62). In vivo microradioautographic analysis of insulin-binding sites in the mouse deferent duct (86) showed the presence of specific insulin binding in the endothelial cells of capillaries and certain fibroblasts in the lamina propria, but the epithelial cells, except for the basal cells, did not show any insulin binding (Figure 3). Endothelial cells are known to be insulin targets (87), and the presence of specific insulin receptors on the vascular endothelial cells has been demonstrated by in vivo radioautography in rat heart capillary (88).…”

Section: Histologic Distribution Of Insulin Receptorsmentioning

confidence: 99%

Histologic distribution of insulin and glucagon receptors

Hayasaki

et al. 1998

Braz J Med Biol Res

Insulin and glucagon are the hormonal polypeptides secreted by the B and A cells of the endocrine pancreas, respectively. Their major physiologic effects are regulation of carbohydrate metabolism, but they have opposite effects. Insulin and glucagon have various physiologic roles, in addition to the regulation of carbohydrate metabolism. The physiologic effects of insulin and glucagon on the cell are initiated by the binding of each hormone to receptors on the target cells. Morphologic studies may be useful for relating biochemical, physiologic, and pharmacologic information on the receptors to an anatomic background. Receptor radioautography techniques using radioligands to label specific insulin and glucagon receptors have been successfully applied to many tissues and organs. In this review, current knowledge of the histologic distribution of insulin and glucagon receptors is presented with a brief description of receptor radioautography techniques.

Autoradiographic distribution of radioactivity from14C-GABA in the mouse

Kuroda

et al. 2000

Microsc. Res. Tech.

We investigated the distribution of radioactivity from 14C‐labeled γ‐aminobutyric acid (GABA) in the mouse by in vivo autoradiography to clarify the tissues that show GABA uptake and/or GABA binding. Male mice were injected intravenously with 14C‐GABA in both the absence and presence of an excess of unlabeled GABA, baclofen and isoguvacine. Whole‐body autoradiography of 3H‐baclofen, a GABAB receptor agonist was also performed. At short intervals after 14C‐GABA injection ( 3 and 6 minutes), very high radioactivity was detected in the kidney cortex, liver, pineal gland, hypophysis, median eminence of the hypothalamus, and cervical ganglion. The hyaline cartilage and glandular part of the stomach showed moderate radioactivity. In the presence of an excess amount of unlabeled GABA, radioactivity in most of tissues decreased significantly, but no significant difference in radioactivity was observed in the presence of baclofen and isoguvacine, agonists of GABAA and GABAB receptors, respectively. Autoradiography of 3H‐baclofen showed that the kidney had high level of radioactivity, whereas the activity in other tissues and organs was similar or lower than in the blood except for the content of the urinary bladder and the pancreas at 15 minutes after injection. These data indicate that radioactivity from incorporated 14C‐GABA into a variety of cells is much higher than that from bound 14C‐GABA to the receptor sites. Our results suggest that GABA can be quickly localized in many organs of the mouse body after 3 minutes following injection, and GABA may serve multiple functions in those organs. Microsc. Res. Tech. 41:116–126, 2000. © 2000 Wiley‐Liss, Inc.