Non-functioning pituitary adenomas: endocrinological and clinical outcome after transsphenoidal and transcranial surgery.

AIM: To study improvement of anterior pituitary function after transsphenoidal and transcranial surgery of non-functioning (NF) pituitary macro- and microadenomas. METHODS: We retrospectively examined 155 patients with NF adenomas preoperatively and 3 months, 1 year and 2 years postoperatively. 130 patients harboured a macroadenoma, 109 underwent transsphenoidal (group one), 21 transcranial surgery (group two). 25 patients presented a microadenoma (transsphenoidal surgery, group three). Endocrine studies included basal serum levels and dynamic testing of anterior pituitary partial function. Clinical symptoms and hormone replacement therapy were documented. RESULTS: Preoperatively, in group one, two and three, somatotropic function was impaired in 85, 90 and 80 %, gonadotropic in 61, 57 and 24 %, corticotropic in 31, 38 and 28 %, thyreotropic in 32, 38 and 12 % and lactotropic in 22, 38 and 32 % cases, respectively. Pituitary functions did not improve significantly after transsphenoidal or transcranial surgery. Presurgically, 63, 62 and 0 % patients complained about visual impairments, 60, 48 and 40 % about headache, 53, 24 and 36 % about fatigue and 28, 33 and 20 % about disturbance of cycle or potency. After transsphenoidal surgery, impaired vision, headache and fatigue improved within 3 months; after transcranial surgery, only headache improved. Preoperatively, pituitary malfunctions were treated adequately. Postsurgically, more patients received adrenal and thyroid hormone substitution, less patients received sex hormones than examinations proved necessary. CONCLUSION: Anterior pituitary function of NF adenoma patients did not improve significantly after transsphenoidal or transcranial surgery. After transsphenoidal surgery, most clinical symptoms normalised within 3 months. In some of the patients, substitution was not optimally adjusted to hormonal impairments.

Dose distribution in hydrocortisone replacement therapy has a significant influence on urine free cortisol excretion.

We investigated the influence of dose distribution in hydrocortisone replacement therapy on urine free cortisol excretion. To this end, we measured 24-hour urine free cortisol (24-h UFC) in 13 patients with hypocortisolism. The patients took 25 mg hydrocortisone/day according to the following schedules: either a single 25 mg hydrocortisone dose at 8:00 a.m., or 15 mg hydrocortisone at 8:00 a.m. and 10 mg hydrocortisone at 2:00 p.m., or 5 mg hydrocortisone at 8:00 a.m., 10:00 a.m., 2:00 p.m., 6:00 p.m. and 10:00 p.m. 24-h UFC decreased significantly with increasing division of the daily 25 mg hydrocortisone dose. When taking 25 mg hydrocortisone in a single morning dose, the mean 24-h UFC was 649 +/- 52 nmol/day (mean +/- SEM). When the daily dose was divided into doses of 15 mg and 10 mg hydrocortisone, 24-h UFC was reduced by 28 % to 466 +/- 39 nmol/day (p < 0.002). After division into five doses of 5 mg, 24-h UFC was reduced by 42.8 % to 371 +/- 36 nmol/day (p < 0.001) compared to the single 25 mg dose. These data demonstrate that consideration of the dose distribution in hydrocortisone replacement therapy when analysing 24-h UFC is of clinical importance.

Inability of rat alveolar macrophages to recycle L-citrulline to L-arginine despite induction of argininosuccinate synthetase mRNA and protein, and inhibition of nitric oxide synthesis by exogenous L-citrulline.

In the present study it was tested whether rat alveolar macrophages (AMphi) convert L-citrulline to L-arginine to maintain nitric oxide (NO) synthesis under conditions of limited availability of L-arginine. Rat AMphi (0.5 x 10(6) cells/well, cultured for 20 h in the absence or presence of 1 microg/ml lipopolysaccharides, LPS), were incubated for 6 h in amino acid-free Krebs solution and nitrite accumulation was determined as a measure of NO synthesis. After culture in the absence of LPS, nitrite in the incubation media was at the detection limit, independent of the addition of L-arginine or L-citrulline. AMphi, cultured in the presence of LPS, produced about 4 nmol per 10(6) cells and 6 h nitrite, and L-arginine enhanced nitrite accumulation in a concentration-dependent manner, maximally about threefold (EC50: 55 microM). In LPS-treated AMphi L-citrulline (up to 10 mM) failed to enhance nitrite accumulation, but rather inhibited it by about 50% in the presence of 100 microM L-arginine, i.e. when NO synthesis was enhanced. L-Arginine in the culture medium was 3H-labelled and its metabolism analysed by HPLC. In medium of AMphi exposed to LPS [3H]-L-arginine was reduced by about 60% after a 20-h culture period and this was almost balanced by an almost equal increase in [3H]-L-citrulline and [3H]-L-ornithine, i.e. L-arginine was markedly consumed. When [14C]-L-citrulline was added to the culture medium of AMphi, no significant formation of [14C]-L-arginine could be detected. On the other hand, argininosuccinate synthetase mRNA (by RT-PCR) and protein (by Western blot) was marginally detectable in control AMphi, but clearly induced after exposure to LPS. Finally, L-citrulline was shown to inhibit L-arginine uptake in a concentration dependent manner, by about 50% at 10 mM. In conclusion, although the expression of argininosuccinate synthetase in rat AMphi can be induced by LPS, AMphi appear not to be able to recycle significant amounts of L-citrulline to L-arginine to maintain sustained NO synthesis. On the contrary, at high concentrations L-citrulline can reduce NO synthesis, and this effect appears to be caused by inhibitory effects on L-arginine uptake.