Peripheral infusion of insulin-like growth factor-I increases the number of newborn oligodendrocytes in the cerebral cortex of adult hypophysectomized rats.

• We have previously shown that recombinant human (rh) IGF-I induces cell proliferation and neurogenesis in the hippocampus of hypophysectomized rats. In the current investigation, we determined the effects of rhIGF-I on proliferation and differentiation in the cerebral cortex. Adult hypophysectomized rats were injected with bromodeoxyuridine (BrdU) to label newborn cells (once a day for the first 5 d), and rhIGF-I was administered peripherally for 6 or 20 d. In the cerebral cortex, the number of BrdU-labeled cells increased after 20 d but not after 6 d of rhIGF-I infusion. This suggests that rhIGF-I enhances the survival of newborn cells in the cerebral cortex. Using BrdU labeling combined with the oligodendrocyte-specific markers myelin basic protein and 2',3'-cyclic nucleotide 3'-phosphodiesterase, we demonstrated an increase in oligodendrogenesis in the cerebral cortex. The total amount of myelin basic protein and 2',3'-cyclic nucleotide 3'-phosphodiesterase was also increased on Western blots of homogenates of the cerebral cortex, confirming the immunohistochemical findings. Also, we observed an increase in the number of capillary-associated BrdU-positive cells, although total capillary area was not increased. rhIGF-I treatment did not affect cortical astrogliogenesis and neurogenesis was not observed. The ability of rhIGF-I to induce cortical oligodendrogenesis may have implications for the regenerative potential of the cortex.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Physiology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Endokrinologi och diabetes (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Endocrinology and Diabetes (hsv//eng)

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Keyword

Age Factors

Animals

Antimetabolites

pharmacokinetics

Astrocytes

cytology

drug effects

Bromodeoxyuridine

pharmacokinetics

Capillaries

Cell Count

Cell Division

drug effects

Cell Survival

drug effects

Cerebral Cortex

blood supply

cytology

Female

Hypophysectomy

Injections

Subcutaneous

Insulin-Like Growth Factor I

pharmacology

Oligodendroglia

cytology

drug effects

Rats

Rats

Sprague-Dawley

Recombinant Proteins

pharmacology

Publication and Content Type

ref (subject category)

art (subject category)